This specimen is consists of a mix of Tetranatrolite, Albite, and Cryolite pseudomorphed after a natrolite crystal. Tetranatrolite was once considered a valid species within the zeolite group, closely related to natrolite and originally described from the famous Poudrette Quarry at Mont Saint-Hilaire, Québec as mineral is considered a more hydrated analogue of natrolite. This specimen is labelled as tetranatrolite; however, the species was discredited in 1999 and is now thought to represent either paranatrolite or gonnardite. At Mont Saint-Hilaire, this mineral occurs widely in the pegmatitic dykes and miarolitic cavities of the nepheline syenite, typically forming an epitactic relationship with natrolite. It appears as overgrowths on natrolite crystals, or as small euhedral crystals and silky fibrous sprays on natrolite, analcime, or microcline. It often forms a friable crust coating natrolite crystals, which commonly show the simple crystal habits typical of the locality. Although its exact classification remains controversial—particularly in relation to gonnardite—this specimen represents rare and intriguing material, making it a valuable addition to any Mont Saint-Hilaire suite or collection focused on discredited or transitional species. Collected by Peter Tarassoff in 1997.
